Accumulation of p53wt following irradiation in both sensitive and resistant B-CLL cells. Western blot analysis of the nuclear protein levels of wild-type (wt) and mutated (mt) p53 at indicated time after irradiation was compared to untreated cells (time 0). According to cell susceptibility to undergo or not apoptosis following irradiation, an equal amount of total proteins derived from 1.5 × 10⁶ B-CLL cells sensitive (A) or resistant (B) both expressing p53wt and resistant cells expressing p53mt (C) was deposited in each lane and evidenced by actin protein level as control. The results are representative analyses of 11 sensitive and 6 resistant samples expressing p53wt as well as 5 resistant B-CLL samples expressing p53mt.